Window and display device including same

ABSTRACT

A window includes a first cover layer, a second cover layer, and a first adhesive part. The first cover layer includes a first non-folding area, a folding area, and a second non-folding area that are arranged in a first direction, and a plurality of first recessed portions recessed from a top surface of the folding area and extended in a second direction intersecting the first direction. The second cover layer is disposed on the first cover layer. The first adhesive part is disposed between the first cover layer and the second cover layer, and includes protrusions disposed in the plurality of first recessed portions of the first cover layer.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a continuation application of U.S. patent application Ser. No.17/200,327, filed Mar. 12, 2021 (now pending), the disclosure of whichis incorporated herein by reference in its entirety. U.S. patentapplication Ser. No. 17/200,327 claims priority to and benefits ofKorean Patent Application No. 10-2020-0083923 under 35 U.S.C. § 119,filed on Jul. 8, 2020 in the Korean Intellectual Property Office (KIPO),the entire contents of which are incorporated herein by reference.

BACKGROUND (a) Technical Field

The disclosure herein relates to a window and a display device includingthe same, and, to a window suitable for a flexible display device foldedand unfolded about a folding axis; and a display device including thesame.

(b) Description of the Related Art

Electronic apparatuses that provide an image to a user, such as smartphones, digital cameras, laptop computers, navigation units, and smarttelevisions include display devices for displaying the image. Such adisplay device generates an image and provides the image to the user viaa display screen.

Recently, various types of display devices have been developed with thetechnological advancements regarding the display devices. For example,various flexible display devices, which may be deformable, foldable, orrollable into a curved shape, have been developed. The flexible displaydevices having diversely deformable shapes may be easy to carry andimprove user's convenience.

00000Among the flexible display devices, a foldable display device maybe folded about a folding axis extending in one direction. The foldabledisplay device may include a flexible display panel and a flexiblewindow disposed on the display panel.

It is to be understood that this background of the technology sectionis, in part, intended to provide useful background for understanding thetechnology. However, this background of the technology section may alsoinclude ideas, concepts, or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior to acorresponding effective filing date of the subject matter disclosedherein.

SUMMARY

The disclosure provides a window suitable for a foldable display deviceand a display device including the window.

An embodiment provides a window that may include a first cover layercomprising a first non-folding area, a folding area, and a secondnon-folding area that may be arranged in a first direction; and aplurality of first recessed portions recessed from a top surface of thefolding area and extended in a second direction intersecting the firstdirection; a second cover layer disposed on the first cover layer; and afirst adhesive part disposed between the first cover layer and thesecond cover layer, wherein the first adhesive part may compriseprotrusions disposed in the plurality of first recessed portions of thefirst cover layer.

The second cover layer may have a thickness less than a thickness of thefirst cover layer.

Depths of the plurality of first recessed portions of the first coverlayer may vary gradually in a direction from a center of the foldingarea toward the first non-folding area or the second non-folding area.

Depths of the plurality of first recessed portions of the first coverlayer may decrease gradually in the direction from the center of thefolding area toward the first non-folding area or the second non-foldingarea.

Depths of the plurality of first recessed portions of the first coverlayer may increase gradually in the direction from the center of thefolding area toward the first non-folding area or the second non-foldingarea.

The first cover layer may include a plurality of second recessedportions recessed from a bottom surface of the folding area and extendedin the second direction.

The plurality of first recessed portions and the plurality of secondrecessed portions may be alternately disposed in the first direction.

The window may further include a plurality of second adhesive partsinserted into the second recessed portions of the first cover layer.

The plurality of first recessed portions may not be formed in the firstand second non-folding areas.

The window may further include a third cover layer disposed below thefirst cover layer, wherein the third cover layer and the second coverlayer may comprise a same material.

The plurality of first recessed portions may be spaced apart from eachother in the first direction.

Each of the plurality of first recessed portions may be defined by afirst inner surface of the first cover layer; a second inner surfacefacing the first inner surface of the first cover layer; and a bottomsurface perpendicular to the first inner surface and the second innersurface of the first cover layer.

A depth of each of the plurality of first recessed portions may be lessthan a thickness of the first cover layer.

The plurality of first recessed portions may be spaced apart from eachother in the first direction or in the second direction.

Each of the plurality of first recessed portions may have a “V” shape ora “U” shape in the second direction.

In an embodiment, a window may include a first cover layer comprising afirst non-folding area, a folding area, and a second non-folding areathat may be arranged in a first direction; and a plurality of patternholes passing through a top surface of the folding area and extended ina second direction intersecting the first direction; a second coverlayer disposed on the first cover layer; and a first adhesive partdisposed between the first cover layer and the second cover layer,wherein the first adhesive part may comprise protrusions disposed in theplurality of pattern holes.

The window may further include a second adhesive layer extended from theplurality of protrusions and disposed below the first cover layer.

The window may further include a third cover layer disposed below thefirst cover layer, wherein the third cover layer and the second coverlayer may comprise a same material.

The plurality of pattern holes may be spaced apart from each other inthe first direction.

In an embodiment, a display device may include a display modulecomprising a folding area foldable with respect to a folding axisextending in one direction; and a window disposed on the display module,the window and the display module being folded together, wherein thewindow may include a first cover layer comprising a plurality ofrecessed portions, each of the plurality of recessed portions beingincluded in a top surface of the first cover layer overlapping thefolding area, and each of the plurality of recessed portions extendingin the one direction; an adhesive part disposed on the first cover layerand comprising protrusions disposed in the plurality of recessedportions in a bottom surface of the adhesive part; and a second coverlayer disposed on the adhesive part.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments of thedisclosure and, together with the description, serve to explainprinciples of the disclosure. In the drawings:

FIG. 1 is a perspective view illustratively showing a display deviceaccording to an embodiment;

FIG. 2 is a perspective view illustratively showing a state in which thedisplay device illustrated in FIG. 1 is folded;

FIG. 3 is an exploded perspective view illustratively showing thedisplay device illustrated in FIG. 1 ;

FIG. 4 is a schematic cross-sectional view illustratively showing thedisplay module illustrated in FIG. 3 ;

FIG. 5 is a schematic cross-sectional view illustratively showing thewindow illustrated in FIG. 3 ;

FIGS. 6 and 7 are views illustratively showing windows according to anembodiment;

FIG. 8 is a view illustratively showing a window according to anembodiment;

FIG. 9 is a schematic cross-sectional view illustratively showing awindow according to an embodiment;

FIG. 10 is a schematic cross-sectional view illustratively showing awindow according to an embodiment;

FIGS. 11A and 11B are perspective views illustratively showing windowsaccording to an embodiment; and

FIGS. 12 and 13 are schematic cross-sectional views illustrativelyshowing windows according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It will be understood that when an element (or a region, a layer, aportion, or the like) is referred to as “being on”, “connected to” or“coupled to” another element in the specification, it can be directlydisposed on, connected or coupled to another element mentioned above, orintervening elements may be disposed therebetween.

Like numbers refer to like elements throughout. Also, in the drawings,the thicknesses, ratios, and dimensions of the elements may beexaggerated for effective description of the technical contents and forclarity.

The term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The terms “and” and “or” may be used in the conjunctive or disjunctivesense and may be understood to be equivalent to “and/or.” In thespecification and the claims, the phrase “at least one of” is intendedto include the meaning of “at least one selected from the group of” forthe purpose of its meaning and interpretation. For example, “at leastone of A and B” may be understood to mean “A, B, or A and B.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. For example, a first element may bereferred to as a second element, and similarly, a second element may bereferred to as a first element without departing from the scope of thedisclosure. The singular forms include the plural forms unless thecontext clearly indicates otherwise.

Also, terms such as “below”, “lower”, “above”, and “upper” may be usedto describe the relationships of the components illustrated in thedrawings. These terms have a relative concept, and are described on thebasis of the directions indicated in the drawings, but are not limitedthereto.

The spatially relative terms “below”, “beneath”, “lower”, “above”,“upper”, or the like, may be used herein for ease of description todescribe the relations between one element or component and anotherelement or component as illustrated in the drawings. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation, in addition tothe orientation depicted in the drawings. For example, in the case wherea device illustrated in the drawing is turned over, the devicepositioned “below” or “beneath” another device may be placed “above”another device. Accordingly, the illustrative term “below” may includeboth the lower and upper positions. The device may also be oriented inother directions and thus the spatially relative terms may beinterpreted differently depending on the orientations.

Additionally, the terms “overlap” or “overlapped” mean that a firstobject may be above or below or to a side of a second object, and viceversa. Additionally, the term “overlap” may include layer, stack, faceor facing, extending over, covering or partly covering or any othersuitable term as would be appreciated and understood by those ofordinary skill in the art. The terms “face” and “facing” mean that afirst element may directly or indirectly oppose a second element. In acase in which a third element intervenes between the first and secondelement, the first and second element may be understood as beingindirectly opposed to one another, although still facing each other.When an element is described as ‘not overlapping’ or ‘to not overlap’another element, this may include that the elements are spaced apartfrom each other, offset from each other, or set aside from each other orany other suitable term as would be appreciated and understood by thoseof ordinary skill in the art.

The phrase “in a plan view” means viewing the object from the top, andthe phrase “in a schematic cross-sectional view” means viewing across-section of which the object is vertically cut from the side.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” may mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the disclosure pertains. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

It will be understood that the term “includes” or “comprises” or “has”or “having” and the variations thereof, when used in this specification,specify the presence of stated features, integers, steps, operations,elements, components, or a combination thereof, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, or combinations thereof.

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings.

FIG. 1 is a perspective view illustratively showing a display deviceaccording to an embodiment. FIG. 2 is a perspective view illustrativelyshowing a state in which the display device illustrated in FIG. 1 isfolded.

Referring to FIG. 1 , a display device DD according to an embodiment maydisplay an image. The display device DD may provide a user with an imageor images through a display surface DS.

According to an embodiment, the display device DD may have two sidesextending in a first direction DR1 and two sides extending in a seconddirection DR2 crossing or intersecting the first direction DR1. Whenviewed in a plan view, the display device DD may have a substantiallyrectangular shape. In this specification, the meaning of “when viewed ina plan” may represent a state when viewed in a third direction DR3perpendicular to the plane defined by the first direction DR1 and thesecond direction DR2.

According to an embodiment, the display device DD may be a flexibledisplay device. For example, the display device DD may be folded andunfolded. By way of example, the display device DD may include a firstnon-folding area NFA1, a folding area FA, and a second non-folding areaNFA2, which may be arranged or disposed in the first direction DR1. Thefolding area FA may be disposed between the first non-folding area NFA1and the second non-folding area NFA2.

FIG. 1 illustratively shows one or a folding area FA and two non-foldingareas NFA1 and NFA2, but the numbers of the folding area FA and thenon-folding areas NFA1 and NFA2 are not limited thereto. The displaydevice DD may include more than two, for example, a plurality ofnon-folding areas and a plurality of folding areas disposed between thenon-folding areas.

Referring to FIG. 2 , the display device DD may be folded about afolding axis FX. The folding axis FX may be parallel to the seconddirection DR2. Here, the first non-folding area NFA1 and the secondnon-folding area NFA2 of the display device DD may face each other.Accordingly, the display surface DS of the display device DD may not beexposed to the outside. For example, the display device DD may bein-folded.

However, the folding shape of the display device DD is not limited tothat described above. For example, the display device DD may be foldedabout a folding axis parallel to the first direction DR1. Alternatively,the display device DD may be out-folded so that the display surface DSmay be exposed to the outside.

FIG. 3 is an exploded perspective view illustratively showing thedisplay device illustrated in FIG. 1 . FIG. 4 is a schematiccross-sectional view illustratively showing the display moduleillustrated in FIG. 3 .

Referring to FIGS. 3 and 4 , the display device DD may include a displaymodule DM and a window WIN disposed on the display module DM.

The display module DM may display an image or images and sense an inputof a user. The display module DM may be a flexible display module. Forexample, the display module DM may be folded about the folding axis FXas illustrated in FIG. 2 .

The display module DM may include a display panel DP, an input sensingpart ISP disposed on the display panel DP, and an anti-reflection layerPOL disposed on the input sensing part ISP.

According to an embodiment, the display panel DP may be an organic lightemitting display panel. By way of example, the display panel DP mayinclude a substrate SUB, a circuit element layer CL disposed on thesubstrate SUB, a display element layer OL disposed on the circuitelement layer CL, and a thin film encapsulation layer TFE disposed onthe display element layer OL.

The substrate SUB may be a flexible substrate. For example, thesubstrate SUB may include polyimide (PI). However, the material of thesubstrate SUB is not limited thereto.

The circuit element layer CL may include an insulating layer, asemiconductor pattern, and a conductive pattern, a signal line, and thelike within the spirit and the scope of the disclosure. The insulatinglayer, the semiconductor layer, and the conductive layer may be formedor disposed on the substrate SUB through coating and deposition methods,and subsequently, the insulating layer, the semiconductor layer, and theconductive layer may be selectively patterned through photolithographyprocesses performed multiple times. Subsequently, the semiconductorpattern, the conductive pattern, and the signal line of the circuitelement layer CL may be formed.

The display element layer OL may be disposed on the circuit elementlayer CL. The display element layer OL may include a light emittingelement. For example, the display element layer OL may include anorganic light emitting material, a quantum dot, a quantum rod, or microLED.

The thin film encapsulation layer TFE may be disposed on the circuitelement layer CL to cover or overlap the display element layer OL. Thethin film encapsulation layer TFE may include an inorganic layer, anorganic layer, and an inorganic layer which may be sequentially stacked.The inorganic layer may include an inorganic material and protect pixelsfrom moisture/oxygen. The organic layer may include an organic materialand protect pixels from impurities such as dust particles.

In the preceding description, the display panel DP is assumed to be anorganic light emitting display panel, but an embodiment is not limitedthereto. For example, the display device DP may be a liquid crystaldisplay device.

The input sensing part ISP may include a plurality of sensors forsensing an external input. The sensors may sense the external input in acapacitive method. The external input may include various types ofinputs such as a portion of the user's body, light, heat, a pen, orpressure.

The anti-reflection layer POL may be disposed on the input sensing partISP. The anti-reflection layer POL may be a film for preventing externallight from being reflected. The anti-reflection layer POL may reduce thereflectivity of external light which may be incident toward the displaypanel DP from above the display device DD. For example, theanti-reflection layer POL may include a phase retarder and/or apolarizer.

According to an embodiment, the display device DM may include aplurality of adhesive members. For example, layers of the display moduleDM may be connected to each other by an adhesive member disposed betweenneighboring layers.

FIG. 5 is a schematic cross-sectional view illustratively showing thewindow illustrated in FIG. 3 . For convenience of description, a firstcover layer CVL1, a first adhesive part AD1, and a second cover layerCVL2 are illustrated as being separated from each other in FIG. 5 .

The window WIN may be disposed on the display module DM to protect thedisplay module DM from external scratches, and folded and unfoldedtogether with the display module DM. Thus, the window WIN used in theflexible display device may be required to have high impact resistanceto protect the display module DM and high flexibility to achieve easyfolding.

The window WIN according to an embodiment may include a plurality ofcover layers to ensure high impact resistance and also have a pattern ina folding portion to ensure high flexibility. Hereinafter, the windowWIN according to an embodiment will be described in more detail.

Referring to FIGS. 3, and 5 , the window WIN may include a first coverlayer CVL1, a second cover layer CVL2, and a first adhesive part AD1.The first cover layer CVL1 may be disposed on the display module DM. Thefirst adhesive layer CVL1 may have optically transparentcharacteristics. For example, the first cover layer CVL1 may includematerials such as transparent glass, polymethylmethacrylate (PMMA), andpolycarbonate PC. However, the material of the first cover layer CVL1 isnot limited to those described above.

The first cover layer CVL1 may include a first non-folding area NFA1, afolding area FA, and a second non-folding area NFA2. Substantially, thefirst non-folding area NFA1, the folding area FA, and the secondnon-folding area NFA2 may be defined or formed in each of the layers ofthe display device DD (see FIG. 1 ).

A first recess RE1 may be defined or formed in the first cover layerCVL1. The first recess RE1 may be defined or formed in a first topsurface UF1 of the folding area FA. The first recess RE1 may be recesseddownward (for example, in a third direction DR3) from the first topsurface UF1. The first recess RE1 may not be defined or formed in thenon-folding areas NFA1 and NFA2.

In an embodiment, the first recess RE1 may be provided in plurality.Each of the first recessed portions RE1 may extend in a second directionDR2. Each of the first recessed portions RE1 may be parallel to thefolding axis FX illustrated in FIG. 2 . The first recessed portions RE1may be arranged or disposed spaced apart from each other in a firstdirection DR1. In the third direction DR3, the depth of each of thefirst recessed portions RE1 may be less than the thickness of the firstcover layer CVL1.

FIG. 5 illustrates that ten of the first recessed portions RE1 may bedefined or formed in the first top surface UF1 of the folding area FA.However, this is merely an example, and an embodiment is not limitedthereto. The number of first recessed portions RE1 defined or formed inthe folding area FA may change.

As a further example, each of the first recessed portions RE1 may bedefined or formed by a first inner surface ISF1, a second inner surfaceISF2, and a bottom surface BF in the first cover layer CVL1. Each of thefirst inner surface ISF1 and the second inner surface ISF2 may beparallel to the plane defined by the second direction DR2 and the thirddirection DR3. The first inner surface ISF1 and the second inner surfaceISF2 may face each other.

The bottom surface BF may be disposed between one or an end of the firstinner surface ISF1 and one or an end of the second inner surface ISF2.The bottom surface BF may be parallel to the first top surface UF1 ofthe first cover layer CVL1. In an embodiment, the bottom surface BF maybe perpendicular to the first inner surface ISF1 and the second innersurface ISF2. Accordingly, the first recess RE1 may have a substantiallyU-shape. However, the shape of the first recess RE1 is not limitedthereto.

The second cover layer CVL2 may be disposed above the first cover layerCVL1. A second top surface UF2 of the second cover layer CVL2 may beparallel to the plane defined by the first direction DR1 and the seconddirection DR2. As an example, the second top surface UF2 may define orformed the display surface DS illustrated in FIG. 1 .

The second cover layer CVL2 may be a chemically reinforced glasssubstrate. For example, the second cover layer CVL2 may be ultra thinglass (UTG). The second cover layer CVL2 may be chemically reinforcedand thus may have high mechanical strength while having highflexibility.

The thickness of the second cover layer CVL2 may be less than thethickness of the first cover layer CVL1 in the third direction DR3. Forexample, the thickness of the second cover layer CVL2 may be less thanabout 100 and the thickness of the first cover layer CVL1 may be greaterthan about 100 However, the thickness of each of the first cover layerCVL1 and the second cover layer CVL2 may be varied depending on the sizeand shape of the display device DD, the radius of curvature of a bentportion, or the like within the spirit and the scope of the disclosure.

According to an embodiment, the first adhesive part AD1 may be disposedbetween the first cover layer CVL1 and the second cover layer CVL2. Thefirst cover layer CVL1 may be attached to the second cover layer CVL2 bythe first adhesive part AD1.

The first adhesive part AD1 may include an optically transparentmaterial. For example, the first adhesive part AD1 may include anadhesive or filler. In an embodiment, the first adhesive part AD1 mayinclude a transparent polymer resin, an optical clear adhesive (OCA), apressure sensitive adhesive (PSA), or the like within the spirit and thescope of the disclosure. However, the material of the first adhesivepart AD1 is not limited thereto.

The first adhesive part AD1 may include a first adhesive layer AL1 and aplurality of protrusions PRT. The first adhesive layer AL1 may be incontact with the first top surface UF1 of the first cover layer CVL1 anda second bottom surface BO2 of the second cover layer CVL2. The firstcover layer CVL1 may include a first bottom surface BO1 that may besubstantially parallel to the second bottom surface BO2 of the secondcover layer CVL2.

The protrusions PRT may extend downward (for example, in the thirddirection DR3) from a bottom surface AL1-B of the first adhesive layerAL1. When viewed in a plan view, the protrusions PRT may overlap thefolding area FA. The protrusions PRT may be disposed in thecorresponding first recessed portions RE1.

Each of the protrusions PRT may have a shape substantially correspondingto the first recess RE1. For example, in an embodiment, each of theprotrusions PRT may have a substantially bar shape extending in thesecond direction DR2. The protrusions PRT may be spaced apart from eachother in the first direction DR1.

The thickness of each of the protrusions PRT may be the same as or aboutthe same as the depth of the first recess RE1 in the third directionDR3. Accordingly, each of the protrusions PRT may be in contact with thefirst inner surface ISF1, the second inner surface ISF2, and the bottomsurface BF in a corresponding portion of the first cover layer CVL1.

However, the shape of the protrusions PRT is not limited to thatdescribed above. For example, the shape of the protrusions PRT may bevaried depending on the shape of the corresponding first recess RE1.

According to an embodiment, since the window WIN may include theplurality of cover layers CVL1 and CVL2, forces applied from the outsideof the display device DD may be evenly distributed to the layers. Thus,the display module DM may be more stably protected.

Also, according to an embodiment, the plurality of first recessedportions RE1 extending parallel to the folding axis FX (see FIG. 2 ) maybe defined or formed in the folding area FA of the first cover layerCVL1, and thus, the window WIN may have a high flexibility. Accordingly,the display device DD may be easily folded and unfolded.

According to an embodiment, optically transparent materials may bedisposed in the first recessed portions RE1 of the first cover layerCVL1, and thus, the first recess RE1 may be prevented from being viewedfrom the outside of the display device DD. Also, the impact resistanceof the window WIN may be further enhanced by the materials disposed inthe first recess RE1.

Hereinafter, a window having a structure different from that in an aboveembodiment will be described. In the following drawings, the samecomponents as those of an aforementioned embodiment are illustrated bythe same reference symbols. Hereinafter, descriptions of the samecomponents as those of the aforementioned embodiment will be omitted,and differences will be mainly described in detail.

FIGS. 6 and 7 are views illustratively showing windows according to anembodiment. In FIGS. 6 and 7 , a central axis CX may be a virtual linethat defines the center of a folding area FA in a first direction DR1.In FIGS. 6 and 7 , a first boundary line BL1 may be a virtual line thatdefines a boundary between the folding area FA and a first non-foldingarea NFA1 in the first direction DR1. In FIGS. 6 and 7 , a secondboundary line BL2 may be a virtual line that defines a boundary betweenthe folding area FA and a second non-folding area NFA2 in the firstdirection DR1.

According to an embodiment, the depths of first recessed portions RE1-1and RE1-2, which may be defined or formed in first cover layers CVL1-1and CVL1-2 of windows WIN-1 and WIN-2, respectively, may vary graduallyin a direction from the central axis CX toward the first boundary lineBL1 or the second boundary line BL2.

Referring to FIG. 6 , the depths of the first recessed portions RE1-1may decrease gradually in the direction from the central axis CX towardthe first boundary line BL1. The depth of a first recess RE1-1A closestto the central axis CX may be greater than the depth of a first recessRE1-1B closest to the first boundary line BL1. Similarly, the depths ofthe first recessed portions RE1-1 may decrease gradually in thedirection from the central axis CX toward the second boundary line BL2.In FIG. 6 , a first adhesive layer or part AL1-1 may be in contact withthe first top surface of the first cover layer CVL1-1 and a bottomsurface of the second cover layer CVL2.

According to an embodiment, the thicknesses of protrusions PRT-2disposed in the first recessed portions RE1-1 may decrease in adirection from the central axis CX toward the first boundary line BL1 orthe second boundary line BL2.

Referring to FIG. 7 , the depths of the first recessed portions RE1-2may increase gradually in the direction from the central axis CX towardthe first boundary line BL1. The depth of a first recess RE1-2A closestto the central axis CX may be less than the depth of a first recessRE1-2B closest to the first boundary line BL1. Similarly, the depths ofthe first recessed portions RE1-2 may increase gradually in thedirection from the central axis CX toward the second boundary line BL2.In FIG. 7 , a first adhesive layer or part AL1-2 may be in contact withthe first top surface of the first cover layer CVL1-2 and a bottomsurface of the second cover layer CVL2.

According to an embodiment, the thicknesses of protrusions PRT-2disposed in the first recessed portions RE1-2 may increase in adirection from the central axis CX toward the first boundary line BL1 orthe second boundary line BL2.

FIG. 8 is a view illustratively showing a window according to anembodiment.

Referring to FIG. 8 , a plurality of first recessed portions RE1-3 andsecond recessed portions RE2 may be defined or formed in a first coverlayer CVL1-3 of a window WIN-3. The first recessed portions RE1-3 andthe second recessed portions RE2 may be defined or formed only in afolding area FA and may not be defined or formed in first and secondnon-folding areas NFA1 and NFA2.

The first recess RE1-3 may be defined or formed in a first top surfaceUF1-3 of the folding area FA. For example, the first recessed portionsRE1-3 may extend downward (for example, in a third direction DR3) fromthe first top surface UF1-3. The second recessed portions RE2 may bedefined or formed in a first bottom surface BO1-3 of the folding areaFA. For example, the second recessed portions RE2 may extend upward (forexample, in a third direction DR3) from the first bottom surface BO1-3.

The second recessed portions RE2 may extend in a second direction DR2.For example, the second recessed portions RE2 may extend in a directionparallel to the folding axis FX illustrated in FIG. 2 .

In a first direction DR1, the first recessed portions RE1-3 and thesecond recessed portions RE2 may be alternately arranged or disposed. Inthe first direction DR1, a second recess RE2 may be disposed betweenneighboring or adjacent first recessed portions RE1-3. A first recessRE1-3 and a second recess RE2, which may be adjacent to each other inthe first direction DR1, may be spaced apart from each other.

A protrusion PRT-3 of a first adhesive part AD1-3 may be disposed in thefirst recess RE1-3. A second adhesive part AD2 may be disposed in eachof the second recessed portions RE2. The second adhesive part AD2 mayinclude the same or similar material as the first adhesive part AD1-3.For example, the second adhesive part AD2 may include an opticallytransparent adhesive or filler.

According to an embodiment, an adhesive layer extending from theplurality of second adhesive parts AD2 and a third adhesive layerdisposed below the adhesive layer may be further provided or disposedbelow the first cover layer CVL1-3. The third cover layer may beattached to the first cover layer CVL1-3 by the adhesive layer. Forexample, the third cover layer may be the same ultra thin glass (UTG) asa second cover layer CVL2.

According to an embodiment, the first recessed portions RE1-3 and thesecond recessed portions RE2 may be defined or formed in the first topsurface UF1-3 and the first bottom surface BO1-3 of the first coverlayer CVL1-3, respectively, and the first recessed portions RE1-3 andthe second recessed portions RE2 may be alternately arranged or disposedin a first direction DR1. Thus, the flexibility of the window WIN may befurther enhanced.

FIG. 9 is a schematic cross-sectional view illustratively showing awindow according to an embodiment.

Referring to FIG. 9 , a window WIN-4 may include a first cover layerCVL1-4, a second cover layer CVL2, and a first adhesive layer AD1-4. Ina third direction DR3, the first adhesive layer AD1-4 may be disposedbetween the first cover layer CVL1-4 and the second cover layer CVL2.

The first cover layer CVL1-4 may include a first non-folding area NFA1,a folding area FA, and a second non-folding area NFA2, which may bearranged or disposed in a first direction DR1. A pattern hole PH may bedefined or formed in a first top surface UF1-4 of the folding area FA.The pattern hole PH may pass through the folding area FA in a thicknessdirection (for example, the third direction DR3). The pattern hole PHmay not be defined or formed in the non-folding areas NFA1 and NFA2.

According to an embodiment, the pattern hole PH may be provided inplurality. The pattern holes PH may extend in a second direction DR2.For example, each of the pattern holes PH may extend parallel to thefolding axis FX illustrated in FIG. 2 .

The pattern holes PH may be arranged or disposed spaced apart from eachother in the first direction DR1. In the third direction DR3, thepattern holes PH may extend from the first top surface UF1-4 of thefirst cover layer CVL1-4 to a first bottom surface BO1-4.

The first adhesive part AD1-4 may include an optically transparentmaterial. For example, the first adhesive part AD1-4 may include anadhesive or filler. In an embodiment, the first adhesive part AD1-4 mayinclude transparent materials such as a transparent polymer resin, anoptical clear adhesive (OCA), and a pressure sensitive adhesive (PSA).However, the material of the first adhesive part AD1-4 is not limitedthereto.

Protrusions PRT-4 of the first adhesive part AD1-4 may be disposed inthe pattern holes PH. The bottom surface of the protrusions PRT-4 may beparallel to the first bottom surface BO1-4 of the first cover layerCVL1-4.

FIG. 10 is a schematic cross-sectional view illustratively showing awindow according to an embodiment.

Referring to FIG. 10 , a first adhesive part AD1-5 may further include asecond adhesive layer AL2. The second adhesive layer AL2 may be disposedbelow a first cover layer CVL1-5.

The second adhesive layer AL2 may extend from protrusions PRT-5. Thesecond adhesive layer AL2 may be integrated or formed integrally withthe first adhesive layer AL1 and the protrusions PRT-5. The secondadhesive layer AL2 may include the same or similar material as the firstadhesive layer AL1 and the protrusions PRT-5. For example, the secondadhesive layer AL2 may include an optically transparent adhesive orfiller.

According to an embodiment, a window WIN-5 may further include a thirdcover layer CVL3. The third cover layer CVL3 may be disposed below thesecond adhesive layer AL2. The third cover layer CVL3 may be fixed tothe first cover layer CVL1-5 by the second adhesive layer AD2.

The third cover layer CVL3 may include the same or similar material asthe second cover layer CVL2. The third cover layer CVL3 may be achemically reinforced glass substrate. For example, the third coverlayer CVL3 may be ultra thin glass (UTG). Similar to the second coverlayer CVL2, the third cover layer CVL3 may be chemically reinforced andthus may have high mechanical strength while having high flexibility.

According to an embodiment, the window WIN-5 may further include thethird cover layer CVL3, and thus, the impact resistance of the windowWIN-5 may be further enhanced.

FIGS. 11A and 11B are perspective views illustratively showing windowsaccording to an embodiment.

Referring to FIGS. 11A and 11B, a plurality of first recessed portionsRE1-6A and RE1-6B may be defined or formed in a first cover layer CVL1-6of a window WIN-6. The first recessed portions RE1-6A and RE1-6B may bedefined or formed in a folding area FA and may not be defined or formedin non-folding areas NFA1 and NFA2. The first recessed portions RE1-6Aand RE1-6B may be recessed downward (for example, in a third directionDR3) from a first top surface UF1-6 of the folding area FA. In FIGS. 11Aand 11B, a first adhesive layer or part AL1-6 may be in contact with thefirst top surface of the first cover layer CVL1-6 and a bottom surfaceof the second cover layer CVL2.

For example, as illustrated in FIG. 11A, the first recessed portionsRE1-6A may be regularly arranged or disposed in a first direction DR1and a second direction DR2. Neighboring or adjacent first recessedportions RE1-6A may be spaced apart from each other in the firstdirection DR1 and the second direction DR2.

When viewed in a plan view, the first recessed portions RE1-6A may havea substantially quadrangular shape. However, the shape of the firstrecessed portions RE1-6A is not limited thereto. For example, whenviewed in a plan view, the shape of the first recessed portions RE1-6Amay be modified into a substantially circular shape, a substantiallypolygonal shape, or the like within the spirit and the scope of thedisclosure.

Protrusions PRT-6A may be disposed in the first recessed portionsRE1-6A. For example, each of the protrusions PRT-6A may have a shapesubstantially corresponding to each of the first recessed portionsRE1-6A. The protrusions PRT-6A may be arranged or disposed in the firstdirection DR1 and the second direction DR2, and the protrusions PRT-6Amay be spaced apart from each other in the first direction DR1 and thesecond direction DR2.

As another example, the first recessed portions RE1-6B may beirregularly arranged or disposed as illustrated in FIG. 11B. Neighboringor adjacent first recessed portions RE1-6B may be arranged or disposedin a zigzag pattern in a second direction DR2. Protrusions PRT-6B may bearranged or disposed in a pattern corresponding to that of the firstrecessed portions RE1-6B.

In the window WIN-6 according to an embodiment, portions of the firstcover layer CVL1-6 may be disposed between the first recessed portionsRE1-6A and RE1-6B adjacent to each other in the second direction DR2,and thus, the durability of the window WIN-6 may be further enhancedthan that of the window WIN according to the aforementioned embodiment.

FIGS. 12 and 13 are schematic cross-sectional views illustrativelyshowing windows according to an embodiment.

The shapes of first recessed portions RE1-7 and RE1-8 of windows WIN-7and WIN-8 may be diversely modified. Referring to FIG. 12 , when viewedin a second direction DR2, a first recess RE1-7 may have a substantially“V” shape. In this case, a protrusion PRT-7 to be disposed in the firstrecess RE1-7 may be modified into substantially the same shape. In FIG.12 , a first adhesive layer or part AL1-7 may be in contact with thefirst top surface of the first cover layer CVL1-7 and a bottom surfaceof the second cover layer CVL2.

Referring to FIG. 13 , when viewed in a second direction DR2, a firstrecess RE1-8 may have a substantially “U” shape. In this case, aprotrusion PRT-8 to be disposed in the first recess RE1-8 may bemodified into substantially the same shape. In FIG. 13 , a firstadhesive layer or part AL1-8 may be in contact with the first topsurface of the first cover layer CVL1-8 and a bottom surface of thesecond cover layer CVL2.

According to an embodiment, the plurality of first recessed portionsextending parallel to the folding axis may be defined or formed in thefolding area of the first cover layer, and thus, the window may havehigh flexibility. Accordingly, the display device may be easily foldedand unfolded.

Although embodiments have been described, it is understood that variouschanges and modifications can be made by one of ordinary skill in theart within the spirit and scope of the disclosure as hereinafterclaimed. Also, embodiments are not intended to limit the disclosure, andall equivalents should be interpreted to be included in the scope of thedisclosure.

What is claimed is:
 1. A window comprising: a first cover layercomprising a first non-folding area and a second non-folding area spacedapart in a first direction, and a folding area disposed between thefirst non-folding area and the second non-folding area and in which aplurality of first recessed portions at least partially removed from theupper surface is defined; a second cover layer disposed on the firstcover layer; and a first adhesive part disposed between the first coverlayer and the second cover layer and comprising a plurality ofprotrusions disposed in the corresponding first recessed portions,wherein each of the plurality of first recessed portions extends along asecond direction intersecting the first direction and is spaced apartfrom each other along the first direction.
 2. The window of claim 1,wherein in a thickness direction of the first cover layer, a depth ofthe plurality of first recessed portions is the same as a thickness ofthe plurality of protrusions.
 3. The window of claim 1, wherein in aplan view, each of the plurality of protrusions is parallel to theadjacent first recessed portions along the second direction.
 4. Thewindow of claim 1, wherein each of the plurality of first recessedportions is defined by: a first inner surface of the first cover layer;a second inner surface facing the first inner surface of the first coverlayer; and a bottom surface disposed between the first inner surface andthe second inner surface of the first cover layer, wherein the bottomsurface is parallel to the top surface of the first cover layer.
 5. Thewindow of claim 1, wherein a distance between adjacent the firstrecessed portions in the first direction is equal to each other.
 6. Thewindow of claim 1, wherein the second cover layer has a smallerthickness than the first cover layer.
 7. The window of claim 1, whereinin a thickness direction of the first cover layer, a depths of theplurality of first recessed portions decrease gradually in the directionfrom the center of the folding area toward the first non-folding areaand the second non-folding area.
 8. The window of claim 1, wherein in athickness direction of the first cover layer, a depths of the pluralityof first recessed portions increase gradually in the direction from thecenter of the folding area toward the first non-folding area and thesecond non-folding area.
 9. The window of claim 1, wherein the firstcover layer is defined with a plurality of second recessed portionswhich is removed from a portion of a bottom surface of the first coverlayer overlapping the folding region.
 10. The window of claim 9, whereinthe plurality of first recessed portions and the plurality of secondrecessed portions are alternately arranged along the first direction.11. The window of claim 10, further comprising a plurality of secondadhesive parts inserted into the corresponding second recessed portions,and an one surface of each of the second adhesive parts exposed from thecorresponding second recessed portions defines the same plane as thebottom surface of the first cover layer.
 12. The window of claim 1,wherein an one surface of each of the plurality of protrusions exposedfrom the corresponding first recessed portions defines a same plane as abottom surface of the first cover layer.
 13. The window of claim 12,further comprising a second adhesive part disposed on the bottom surfaceof the first cover layer, wherein in the folding area, the secondadhesive part contacts the one surface of each of the plurality ofprotrusions.
 14. The window of claim 13, further comprising a thirdcover layer disposed below the second adhesive part, wherein the thirdcover layer and the second cover layer comprise a same material.
 15. Thewindow device of claim 1, wherein a width of each of the plurality offirst recessed portions in the first direction decreases away from thefirst adhesive part.
 16. The window device of claim 15, wherein a shapeof each of the plurality of first recessed portions has a “V” shape or a“U” shape in the second direction.
 17. The window of claim 1, wherein athickness of the second cover layer is smaller than a thickness of thefirst cover layer.
 18. The window of claim 1, wherein the folding areais folded based on a folding axis extending in the second direction. 19.A window comprising: a first cover layer comprising a first non-foldingarea and a second non-folding area spaced apart in a first direction,and a folding area disposed between the first non-folding area and thesecond non-folding area and in which a plurality of first recessedportions at least partially removed from the upper surface is defined; asecond cover layer disposed on the first cover layer; and a firstadhesive part disposed between the first cover layer and the secondcover layer and comprising a plurality of protrusions disposed in thecorresponding first recessed portions, wherein each of the plurality offirst recessed portions is spaced apart from each other in the firstdirection and in a second direction crossing the first direction. 20.The window of claim 19, wherein in a thickness direction of the firstcover layer, a depth of the plurality of first recessed portions is thesame as a thickness of the plurality of protrusions.